As a new display technology, the electrophoretic display device has advantages such as reflective light emitting, low power consumption, super lightness, super thinness, capability of keeping the display state for a long time after power off, and so on. Currently, the electrophoretic display device has been widely used in the fields of electronic book, electronic tag, etc, and has very good market prospect.
An electrophoretic display device typically comprises an array substrate, an opposite substrate (or referred to as protection plate), display medium such as electrophoretic film arranged between the array substrate and the opposite substrate, a peripheral driving circuit, and so on. The peripheral driving circuit comprises a data line driving integrated circuit (IC) and a gate line driving integrated circuit. As shown in FIG. 1, the electrophoretic film comprises multiple micro-capsules 1. Each micro-capsule 1 contains white particles 2 with positive charges and black particles 3 with negative charges floating in liquid. The micro-capsules 1 are sandwiched between the upper substrate 4 (opposite substrate) and the lower substrate 5 (array substrate). When the lower substrate 5 is applied with a positive electric field, the white particles with positive charges move to the top of the micro-capsules 1, and the corresponding locations are shown as white. On the contrary, when the lower substrate 5 is applied with a negative electric field, the black particles with negative charges move to the top of the micro-capsules 1, and the corresponding locations are shown as black.
Currently, the gray levels of the electrophoretic display are implemented by applying voltage pulses of a particular period, which can be expressed as NGrad=time×Voltage, where NGrad is the gray level, time is the voltage pulse time, and Voltage is the voltage on the data line. The voltage on the data line is typically fixed at 0V or ±15V, and the displayed gray level is determined by the voltage pulse time. In other words, the longer the voltage pulse time, the higher the brightness, and vice versa, as shown in FIG. 2.
However, because the dielectric characteristic of the electrophoretic film changes with the temperature, in the prior art, each type of electrophoretic film is provided with a look up table corresponding thereto. The relationship between the displayed gray levels and the voltage pulse widths is stored in the look up table. According to the temperature characteristic of the electrophoretic film, the required voltage pulse time is different for a different temperature, i.e., the voltage pulse width is also different. In general, in order to display the same gray level, the driving voltage pulse time required for a high temperature is shorter than the driving voltage pulse time required for a low temperature, i.e., the voltage pulse width is smaller.
In the prior art, in order to make the look up table of the electrophoretic film, it is needed to measure the dielectric characteristics of the electrophoretic film under different temperatures, calculate the required voltage pulse widths, and then store the correspondence between the temperatures and the voltage pulse widths in a chip as the look up table for subsequently driving the electrophoretic display device. However, with the prior art, the workload for the experiments on the temperature characteristics of the electrophoretic film is large, resulting in low production efficiency and occupying storage space.